Re: [PATCH v4 8/8] iio: adc: ad4030: Add support for ADAQ4216 and ADAQ4224

[David Lechner <dlechner@baylibre.com>]

On 10/8/25 8:51 AM, Marcelo Schmitt wrote:

...

> +static const int adaq4216_hw_gains_db[] = {
> +	-10,	/* 1/3 V/V gain */
> +	-5,	/* 5/9 V/V gain */
> +	7,	/* 20/9 V/V gain */
> +	16,	/* 20/3 V/V gain */
> +};

This is only being used for ARRAY_SIZE() and can be dropped.

> +
> +/*
> + * Gains computed as fractions of 1000 so they can be expressed by integers.
> + */
> +static const int adaq4216_hw_gains_vpv[] = {
> +	MILLI / 3,		/* 333 */
> +	(5 * MILLI / 9),	/* 555 */
> +	(20 * MILLI / 9),	/* 2222 */
> +	(20 * MILLI / 3),	/* 6666 */
> +};
> +
> +static const int adaq4216_hw_gains_frac[][2] = {
> +	{ 1, 3 },  /* 1/3 V/V gain */
> +	{ 5, 9 },  /* 5/9 V/V gain */
> +	{ 20, 9 }, /* 20/9 V/V gain */
> +	{ 20, 3 }, /* 20/3 V/V gain */
> +};
> +

...

> @@ -432,7 +533,14 @@ static int ad4030_get_chan_scale(struct iio_dev *indio_dev,
>  
>  	*val2 = scan_type->realbits;
>  
> -	return IIO_VAL_FRACTIONAL_LOG2;
> +	/* The LSB of the 8-bit common-mode data is always vref/256. */
> +	if (scan_type->realbits == 8 || !st->chip->has_pga)
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +
> +	*val = st->scale_avail[st->pga_index][0];
> +	*val2 = st->scale_avail[st->pga_index][1];

Instead of writing over val and val2, it would make more sense to
move the if up a bit, invert the condition, and have it return early.

> +
> +	return IIO_VAL_INT_PLUS_NANO;
>  }
>